A drill chuck is known having an adapter shaft which is held nonrotatably with axial motion play in the drill chuck and formed for receipt in a tool holder of a hammer drill machine. An axial passage is provided for the adapter shaft through which the hammering action of the adapter shaft is transmittable to the end of a drill held in the drill chuck between centrally adjustable chuck jaws.
Such a drill chuck is described for example in German Open Patent Application No. 28 42 783. It allows other drills to be driven with the hammer drill machine instead of the special drill tools designed to fit the tool holder of the hammer drill machine, since they are held in the drill chuck in adjustable clamp jaws fitting the diameter of the drill shaft. The drill chuck with the adapter shaft is inserted in the tool holder of the hammer drill machine, the end of the adapter shaft being formed like the end of the special drill tools fitting the tool holder of the hammer drill machine. Thus the adapter shaft has an axial mction play limited by a rigid stop not only in the tool holder of the hammer drill machine but also in the drill chuck so that the hammer action of the hammer drill machine can be transmitted as unimpaired as possible through the drill chuck to the drill held axially slidably in the drill chuck. If however only simple rotation of the drill is desired and the drill is to be clamped rigidly between the chuck jaws, the axial motion play of the adapter shaft can be very disturbing because it impairs the precision of the drilling process.